The invention relates to a device for selectively preventing the flow of ink in ink printing equipment such as office, data or telex machines and the like, in which ink is supplied to the printing head from a replaceable ink reservoir, and in which a hollow needle in the ink supply line to the printing head extends into the ink reservoir and is provided with an aperture adapted to be in communication wich such ink.
For creating curved shapes or alphanumerical symbols on carrier materials, the use of printing arrangements in which ink is applied directly to the carrier material is well known. Inked mosaic printers and the like are typical examples for this purpose. Arrangements have become known (German DE-OS 24 60 573, DE-OS 25 43 452, DE-OS 26 10 518) in which the ink is supplied to the printing head involved from a replaceable ink reservoir. In this case a hollow needle which forms the inlet end of the ink supply line to the printing head, extends through the wall of the ink reservoir or through a sealing plug in the wall of the reservoir, whereby the ink fluid has access to the inlet aperture in the hollow needle. The wall of the ink reservoir or the sealing plug therein is formed of a resilient material such that the opening through which the hollow needle passes will close up and seal itself upon removal of the hollow needle. This enables, for example, the replacement and storage of ink reservoirs, even when only partially empty.
One desirable objective in a structure such as that described, is to insure that the flow of ink from the reservoir to the printing head can be prevented when the machine is not operating, and in particular during servicing or transportation of the machine. This objective should be so achieved that when the position of the machine is to be altered or when it is jolted in transit no ink can escape from the nozzles in the printing head and produce a messy condition. Arrangements have become known (German DE-OS 23 21 273, DE-OS 23 62 576), in which the ink nozzles are directly covered when the printing head is in a particular position so that no ink can escape therefrom. Arrangements are also known (German DE-OS 24 57 643, DE-AS 22 62 327) in which stop or shut off valves are disposed in the ink supply line between the ink reservoir and printing head.